A randomized clinical trial of maternal-fetal HIV transmission is proposed which will directly compare the efficacy of AZT alone with AZT + 3TC in 1200 HIV-infected Indian women enrolled over a period of 24 months. In addition, the effect of length of therapy will also be assessed: more than 40% of this cohort will be enrolled after 36 weeks of gestation and 30% will be enrolled when they present in labor. This study will also compare the rates of post-partum maternal viral AZT resistance and the morbidity and mortality of mother/infant pairs in the 2 treatment arms. In addition, this study will characterize factors that promote women's participation in clinical trials to assist future trials, as well as implementation of clinical and behavioral HIV prevention interventions. This study will provide an opportunity to identify and design future interventions, and could more rapidly focus resources on specific causes of postpartum morbidity and mortality for mothers and infants in developing countries.